[AG-TECH] echo-cancellation on the cheap?

Jay Beavers jbeavers at microsoft.com
Fri Feb 1 11:07:12 CST 2002

FYI, Microsoft has simple echo cancellation, gain control, and noise
reduction built into Windows XP as part of the Windows Messenger
product.  It's limited in that it is targeted at desktop video
conferencing / VoIP 1-1 scenarios.  The echo cancellation is
specifically tuned for the 8'x10' one speaker environment and it
requires specific hardware -- a list of about 15 PCI based sound cards
in which the speakers and mike are both attached to the sound card.  No
USB devices (mikes or speakers) are supported.

Due to these limitations, I haven't pursued using these capabilities in
our distributed classroom work to date.  I do know there is work afoot
to improve these signal processing capabilities in future OSes, though
this will be a few years off.  I would imagine that the desktop and
conference room scenarios will at some point be covered by 'in the OS
echo cancellation / noise reduction', however I doubt we'll ever see the
'eight mikes muxed plus a wireless speaker mike' of an auditorium /
large workspace handled.

On the topic of 'decreasing the size / cost of an AG node', based on our
work to date we feel it's reasonable to support limited AG participation
(five 320x240 streams) from a desktop.  Our candidate desktop for this
is a Dell Precision Workstation 340.  Cost is around $1500 plus display
devices.  We're also starting to pay attention to the high end laptops,
as they're already to the point where two way conferencing will work and
potentially more.  We're actively testing in this space and will talk
about it at the AG Retreat.

 - jcb

-----Original Message-----
From: Brian Gleason [mailto:bgleason at insors.com] 
Sent: Friday, February 01, 2002 8:38 AM
To: 'Bob Riddle'; ag-tech at mcs.anl.gov
Subject: RE: [AG-TECH] echo-cancellation on the cheap?

Yes inSORS currently is working with and deploying nodes ranging from
conference rooms (sourced, staged, installed and supported)down to a
laptop/desktop node that works nicely. Distributed workers could join
sesions from remote facilities quite easily and quite cheaply.  What we
a "grid station" is a one server, one projector node that works well in
small area.  Our stantdard two server node uses up to four projectors.
Flexibility is key, every case seems to be different from the last.


Brian Gleason
inSORS 312-786-9169

-----Original Message-----
From: owner-ag-tech at mcs.anl.gov [mailto:owner-ag-tech at mcs.anl.gov]On
Behalf Of Bob Riddle
Sent: Friday, February 01, 2002 9:34 AM
To: ag-tech at mcs.anl.gov
Subject: Re: [AG-TECH] echo-cancellation on the cheap?

I'm not so sure that such a "small version" is too far out of that
$10K-20K range given the faster hardware & the work done by Insors &
being done by Microsoft to reduce the number of machines required to
support the AG software.

One could speculate that you might be able to run all necessary
processes on one computer (say a fast SMP) using table top
echo-cancellation mics (no Gentner need) and inexpensive projectors
(don't need 2000 lumens for  a conference room) .... I think you're
close to that dollar amount.

I've wondered if you could point multiple vrm/arm-eventlistener's to the
same DRM on the AG display machine.  We actually use some cheap baluns
to sometimes move our video signals through cat5 cable - I could image
having 4 different offices each having a "camera" and a RAT
participating in the conference .... I realize this abuses the notion of
sharing "meeting rooms" but I think it might help drive devlopment
toward more affodable nodes.  I also would like to have every meeting
room so equipped.

Have you tried using the VRVS AG support for receiving an AG seminar of

David E. Bernholdt wrote:

>While Gurcharan raises a valid issue, from my point of view it is a
>matter of "ease" of deployment.
>We have a single AG node at ORNL right now, and for a combination of
>practical and political reasons, its located 10 min walk from my
>office (even though I built it), and at least that far from the
>majority of prospective users.  That means usage of the AG node
>requires conscious intent.
>I'd like to be able to have an AG in every conference room in our
>Division, and looking further forward, I'd even like to have "personal
>AG" capabilities in each office -- maybe not the full AG, but enough
>to have reasonable meetings with 1-2 people at each of a couple sites,
>or to receive an AG-cast seminar.  I think this level of accessibility
>to the facilities would do a lot to promote the Access Grid.
>So if each node costs $70k, it is a lot harder to get people to spring
>for lots of them.  I don't know exactly where the thresholds are (and
>they'll vary by institution), but I would guess that if you could do a
>small conference room AG node for say $10-20k, people would happily do
>it.  And say at $5k, a personal AG node in every office is not
>Cost is not the only thing inhibiting wider deployment, but it is a
>significant one for most organizations.
>David E. Bernholdt                   |   Email: bernholdtde at ornl.gov
>Oak Ridge National Laboratory        |   Phone: +1 (865) 574 3147
>http://www.csm.ornl.gov/~bernhold/   |   Fax:   +1 (865) 574 0680

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